Hair spray formulations typically comprise a solution of a polymer, the fixative, in water/alcohol mixtures. The polymeric materials which are typically used in hair spray formulations are soluble in water or water/alcohol mixtures and are derived from N-vinyl-pyrrolidinone or N-vinylpyrrolidinone and one or more other vinyl monomers such as vinyl acetate, acrylate and methacrylate esters and/or styrene compounds. When applied to hair and allowed to dry, the polymeric material provides human hair body, consistency, firm texture, and, in general, maintains the hair in a desired arrangement.
Significant amounts of volatile organic compounds such as alcohols are present in such hair spray formulations to facilitate rapid drying of the polymer solution. Environmental concerns continue to encourage the development of hair spray formulations which contain very little and preferably no volatile organic compounds. Attempts to omit the volatile organic component of hair sprays have failed to produce formulations which have acceptable drying times, particularly when the water level exceeds about 55% by weight of the formulation.
U.S. Pat. No. 4,300,580 describes hair spray formulations containing a water-dispersible or water-dissipatible linear sulfo-polyester fixative in a water/alcohol mixture. Such formulations are fast drying and have good hair holding properties but possess the disadvantage of being very difficult to remove from the hair. For example, prolonged washing is required to completely remove the water dispersible, linear polyester fixative to obtain hair with no tacky or sticky feel. In an effort to overcome the fixative removal problem, U.S. Pat. No. 4,300,580 teaches the addition of certain water soluble polymers to formulations containing the water-dispersible, linear polyester. The use of poly(alkylene glycols) such as poly(ethylene glycol) is disclosed. However, when such formulations containing a combination of the poly(alkylene glycol) and water dispersible, linear polyester are applied to hair and allowed to dry, the fixative causes a matting of the hair. Such matting hinders combing, brushing and styling of hair. It is important to note that U.S. Pat. No. 4,300,580 recommends in column 4, lines 36-38, a "nonaerosol" method of application of the hair spray formulation.
U.S. Pat. No. 4,150,216 discloses grooming formulations containing branched sulfo-polyesters. Difficulty, however, is encountered in maintaining the specified molecular weight range of 600 to 5,000. Slight variations in the condensation temperatures and/or times results in branched polymers having molecular weights which exceed the desired values and which have poor film forming characteristics, i.e. they are hard and brittle, and are not readily water dispersible or soluble as required in hair spray formulations.
Copending commonly assigned U.S. patent application Ser. No. 07/892,297 discloses water based, film forming formulations which contain as the fixative a combination of (1) a sulfonate containing, water-dispersible or water-dissipatible, linear polyester and (2) a water-soluble, polyvinyl lactam polymer. While the glass transition temperature (Tg) of the polyester is not specified, the application lists commercially available polyesters which have a Tg of from 29.degree. C. to 55.degree. C.
The present inventors have unexpectedly discovered that aerosol hair spray formulations wherein the fixative is a combination of two polymeric materials: (1) a sulfonate containing, water dissipatible, linear polyester having a Tg of about 36.degree. C. to about 40.degree. C. and (2) a water soluble, poly-vinyl lactam polymer, exhibit improved properties over aerosol hair sprays containing a sulfo-polyester having a Tg outside of said range. The aerosol hair spray formulations of the present invention do not have the disadvantages described hereinabove, such as tackiness, matting and difficulty in removal. Moreover, the aerosol hair spray formulations do not contain any volatile organic compounds other than propellant.